Many machines are available today for breaking the bead of a pneumatic tire. One such machine is shown in U.S. Pat. No. 4,969,498, issued to Sheets on Nov. 13, 1990, entitled TIRE BEAD BREAKER. This bead breaking device features a levered foot member that is stabilized by an elongated upper bar. Another such machine is shown in U.S. Pat. No. 3,113,609, issued on Apr. 5, 1961 to Bishman for TIRE CHANGER. The Bishman tire changer apparatus comprises a center shaft that supports a wheel that is secured in the device by a wheel chuck and retainer pin. A mounting or demounting tool is placed between the tire and the rim. A bead breaking foot is employed to bear against the tire and separate it from the wheel rim.
In U.S. Pat. No. 4,222,426, issued to Brosene, Jr. on Sep. 16, 1980, entitled BEAD BREAKER MECHANISM FOR A TIRE CHANGING MACHINE, a bead breaker is shown that employs a pivoting bead breaking foot. The pivoting foot adjusts itself into the proper bead breaking position, thus pushing the tire away from the rim.
In U.S. Pat. No. 4,335,772, issued to Bubik et al on Jun. 22, 1982 for TIRE CHANGING MACHINE, a bead breaking mechanism is illustrated wherein upper and lower bead breaking shoes are hydraulically, bi-directionally actuated upon diametrically opposite sides of the wheel.
In U.S. Pat. No. 4,059,140, issued on Nov. 22, 1977 to Sedgwick, entitled TIRE CHANGING MACHINE, a hydraulic cylinder with a bead engaging tool is depicted. The cylinder pivots so the bead engaging tool will bear against the bead of the tire.
In U.S. Pa. No. 3,142,330, issued to Nelson on Jul. 28, 1964 for MACHINE FOR UNSEATING TIRE BEADS, a machine is illustrated that provides a lever system that pivots about a center stanchion. Two pistons are used to control the pusher foot placement.
In U.S. Pat. No. 4,462,451, issued to Ogren on Jul. 31, 1984, entitled METHOD AND APPARATUS FOR REMOVING TIRES FROM RIMS, a tire is dismounted from its rim by a ram that first pushes and then pulls the rim from the tire. The push force is directed away from the rim.
All of the aforementioned machines work fairly well, in that they all accomplish their intended purpose of breaking the bead on tires. However, as any tire mechanic will verify, different types of machines present individualized drawbacks, and there are large discrepancies between units with respect to their convenience, portability, and cost.
Generally, those machines that have levered or leveraged pivot arms present cumbersome and overly complicated apparatuses that are often difficult to position properly with respect to the tire and wheel.
Many of the known devices are heavy, non-portable units, designed to be rugged and powerful in order to break the bead on heavy duty tires, such as truck and construction equipment type tires. Such machines, unfortunately, are often expensive and difficult to operate.
Many of the smaller portable devices are dependent on human force to work and do not supply enough power to break the beads on truck or heavy duty construction equipment. Also, small portable units for heavy duty construction equipment tires are very slow to operate and require frequent remounting to the rim to break the bead on the entire diameter.
Most breakers apply the force out on the sidewall of the tire where the sidewall flexes away, thus making it difficult to break the bead.
The present invention seeks to provide a bead breaking machine that is easy to operate, uncomplicated, portable, powerful, fast, lightweight, inexpensive, and which easily breaks the bead of even the heaviest duty truck, aircraft and construction equipment type tires, as well as smaller, light duty tires.
The current invention features a bead breaker apparatus that comprises a rugged, lightweight, upright frame. The frame is mounted upon a base having wheels that provide portability for the unit. The frame supports a pivoting hydraulic ram, upon which a bead breaking shoe is positioned upon a distal end. The frame also provides several pivot points for height adjustable arms that guide the shoe arcuately with respect to a tire wheel. The base supports a wheel positioning assembly, consisting of a locating extension with a rotatable pan upon which a tire and wheel are mounted. The pan is not always necessary as the tire can be simply placed under the ram foot with only a stop pin to keep it from sliding. The rotatable pan allows the bead breaking operator to rotate the tire with respect to the bead breaking shoe and ram apparatus. In this manner, the bead breaking machine can exert pressure upon many points of the tire about the full circumference of the wheel rim. Using this device to accomplish the bead breaking task is unexpectedly easy and efficient. The directed force of the hydraulically manipulated bead breaking shoe acts both inwardly and downwardly upon the tire bead in a direction toward the center of the wheel rim, providing for the unseating and demounting of some of the heaviest duty tires.